So if made a large scale business that included small restaurants I would be relying on their "honor" to send in the sha256 to show a sale? That's not good.
That's more or less correct. But, the customer who is tracking their percentages earned would know that their purchases were not accounted for.
Unless they were unknowingly at a participating vendor. How long does it usually take to get this information back. Is it same day or is there a longer delay? Thanks for the information by the way.
If I recall correctly, we sent a daily feed to Upromise. I don't know how often or when they updated their totals.
Maybe you could go further upstream? Consider integrating with POS systems, merchant account providers, or payment gateways.